Booster seat



FIG. 1 is a perspective view of a booster seat showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a plan view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a left-side elevational view thereof;

FIG. 6 is a right-side elevational view thereof; and,

FIG. 7 is a rear elevational view thereof.

The ornamental design for a booster seat, as shown and described. 